1. Field of the Invention
The present invention relates to a needle extension/retraction mechanism used in a stator winding gun head of a coil winding machine.
2. Description of the Related Art
An alternating current (AC) motor is an electric motor driven by AC that is typically supplied at a constant frequency. Varying frequency AC is also employed to vary the speed of some AC motors. The AC motor typically has two basic parts, an outside (often stationary) stator having coils arranged to produce a rotating magnetic field as the current is supplied thereto, and an inside rotor that often includes an output shaft. The rotor produces a second rotating magnetic field that interacts with the magnetic field of the stator to produce rotary motion of the output shaft. The magnetic field of the rotor may be produced by permanent magnets, reluctance saliency, or electrical windings.
Linear AC motors operate on similar principles as rotating motors but have their stationary and moving parts arranged in a straight line configuration, to thereby produce linear motion instead of rotational motion.
Depending on the configuration of the motor the stator may act as the field magnet, interacting with the rotor, which can be referred to as an armature in this example, to create motion. Or the stator may act as the armature, receiving its influence from moving field coils on the rotor. The first DC generators and DC motors put the field coils on the stator, and the power generation or motive reaction coils on the rotor. This configuration needs a continuously moving power switch, which has come to be called a commutator that is used to keep the magnetic fields correctly aligned across the spinning rotor. The stator can be either a permanent magnet or an electromagnet. Where the stator is configured as an electromagnet, the coils which energize the stator are collectively referred to as the field coil or the field winding.
In order to create a working stator a winding of insulated electrically conductive wire is used to form the stationary winding in the rotary or linear motor. The stator in an AC motor is also a wire coil, called a stator winding, which is built into the motor. When this coil is energized by AC power, a rotating magnetic field is produced. The stator windings are arranged to have a very low resistance and the winding is also electrically insulated from the frame of the motor. While motor stator windings have been discussed herein, the stator windings of the motor are identical to a generator armature that has a like amount of poles.
A needle winding machine is often used to feed the wire back into the crevices between ferrous pole members of the stator. The prior art needle winding machines have typically used a rotational mechanism to extend and retract the needle, with such an arrangement allowing up to 28% movement of the needle as compared to the body of the needle housing. This restricts the depth of the winding dimension, particularly when the rotor size is relatively small, for example when high magnetic strength magnets are used as part of the rotor design.
What is needed in the art is in an economic way in which the depth of movement of a needle in a needle coil winding machine is controllably extended and retracted to a greater degree than the prior art.